Affiliation:
1. Division of Functional Materials and Nanodevices Ningbo Institute of Materials Technology and Engineering Chinese Academy of Sciences Ningbo 315201 China
2. Division of Functional Materials and Nanodevices Ningbo Institute of Materials Technology and Engineering Hangzhou Bay Campus Chinese Academy of Sciences Ningbo 315300 China
3. Zhejiang Provincial Engineering Research Center of Energy Optoelectronic Materials and Devices Ningbo Institute of Materials Technology and Engineering Chinese Academy of Sciences Ningbo 315201 China
4. Faculty of Electrical Engineering and Computer Science Ningbo University Ningbo Zhejiang 315211 China
5. Department of Mechanical Materials and Manufacturing Engineering University of Nottingham Ningbo China Ningbo Zhejiang 315100 China
Abstract
AbstractInorganic perovskite quantum dots (QDs) have garnered significant attention due to their outstanding optical properties. However, perovskite quantum dot light‐emitting diodes (Pe‐QLEDs) still face challenges related to their fluorescence efficiency and electron injection. First, the electron transport layer (ETL) leads to severe non‐radiative recombination due to fluorescence quenching in CsPbI3 QDs. Second, there is an electron injection imbalance resulting from low electron injection efficiency, leading to reduced non‐radiative recombination and external quantum efficiency. To address these issues, this study introduces two interface layer materials with different electron affinities, 1,3,5‐Tris(3‐pyridyl‐3‐phenyl)benzene (TmPyPB) and 2,4,6‐Tris(3′‐(pyridine‐3‐yl)biphenyl‐3‐yl)‐1,3,5‐triazine (TmPPPyTz). These materials not only passivated defects on the surface of CsPbI3 QDs films but also effectively prevented the fluorescence quenching of CsPbI3 QDs by the PO‐T2T (ETL). TmPPPyTz, with a relatively lower LUMO energy level, further improved energy level matching, significantly enhancing electron injection efficiency. Ultimately, using interface engineering with the TmPPPyTz interface layer, the devices achieved an outstanding 25.80% champion‐level external quantum efficiency (EQE) for Pe‐QLEDs with only a sub‐bandgap voltage of 1.7 V and half‐life (T50) is 17.99 h at 100 nits. This research provided an effective method to enhance the performance of CsPbI3 Pe‐QLEDs, addressing long‐standing issues inhibiting their efficiency.
Funder
National Basic Research Program of China
Subject
Atomic and Molecular Physics, and Optics,Electronic, Optical and Magnetic Materials